The phrase "a dark age of" is correct and usable in written English.
It can be used to describe a period characterized by a lack of progress, enlightenment, or cultural development, often in a historical context.
Example: "The fall of the empire led to a dark age of ignorance and superstition that lasted for centuries."
Alternatives: "an era of decline" or "a period of stagnation".
Seldon's calculations forecast a dark age of 30,000 years.
I believe our country risks being thrown into a dark age of medical research.
Britain's Muslim community faces a "dark age of injustice", one of the country's leading civil liberties lawyers said last night.
Time will judge the Bush years as a dark age of falsification, suppression and distortion of the truth.
He calls his sanctuary the Foundation and designs it to withstand a dark age of ignorance, barbarism, and warfare he predicts will last for 30,000 years.
Instead, what should be the golden age of education, work and personal development is for millions a dark age of denied opportunities and immoveable barriers.
"Innovation has to slow, but we are not going to enter a Dark Ages of Innovation," said Steven Chaddick, chief strategist of Ciena, a leading manufacturer of switching products for both long-distance and metropolitan area networks.
At the same time deeply conservative and thoroughly revolutionary, ISIS promises to change the world by plunging it back into a Dark Ages of beheadings and Twitter.
The Dorians swept away the last of the declining Mycenaean and Minoan civilizations of southern Greece and plunged the region into a dark age out of which the Greek city-states began to emerge almost three centuries later.
Overloaded with talent, they are basketball impressionists following a darker age of rugged realists.
The surviving works comprise a literary tradition extending from the 7th century ce to the present; during all this time there was never a "dark age" devoid of literary production.
